The absence of call screening in network-based voicemail systems constitutes one of the biggest hindrances to the penetration of such systems into US and other markets. Call screening and visual Message Waiting Indicator (MWI via blinking light) are two of the biggest Telephone Answering Machine (TAM) selling features that are generally unavailable through network-based voicemail. Telephone handsets and answering machines at customer premises have traditionally provided these features. A common solution in US markets is to use a Telephone Answering Machine on location (i.e., at home, in the office, etc.), to provide such capabilities. Although network-based voicemail provides many advantages over location-based TAMs, network-based voicemail does not easily provide these two vital capabilities. This causes many subscribers in these markets to prefer home-located TAMs to network-based voicemail, despite other limitations of these TAMs. This technological gap causes network operators to lose potential voicemail air time, and it leaves subscribers with limited functionality.
U.S. Pat. No. 6,310,939 issued Oct. 30, 2001 assigned to Lucent Technologies, Inc. and entitled “Method and apparatus for screening a call as the call is transmitted to voice mail” discloses a screening and monitoring capability for switch based voice messaging systems that allows a called party to hear the caller's voice as the caller leaves a message and to break in to start a normal telephone discussion if the caller or the caller's subject warrants such action. A network service feature is provided that controls the bridging of the connections to the voice mail and the called party's telephone station. The service feature turns the voice mail off and destroys the connection if the monitoring called party speaks.
The approach disclosed in U.S. Pat. No. 6,310,939, incorporated herein by reference, is described only in relation to PSTN networks. However, PSTN network switch-based solutions have the following disadvantages:
Complexity: They require Advanced Intelligent Network Capabilities from the switch. These are not necessary supported by all switches.
Each switch might have its own implementation, so a user might have different user experiences using different switches.
Also in order to provide this service, the telephony switch must use two telephony ports for the whole duration of the call.
U.S. Pat. No. 6,353,660 (Burger et al.) issued Mar. 5, 2002, assigned to SS8 Networks, Inc. and entitled “Voice call processing methods” discloses a call screening method that allows a subscriber to screen calls made to the subscriber from callers using the PSTN while the subscriber may use another communications medium, such as VoIP. An enhanced services platform (ESP) receives a first call from a caller using a particular public telephone number for the particular subscriber. The ESP identifies the particular public telephone number for the particular subscriber. The ESP accesses a database storing a public telephone number and a private packet-based address for subscribers to retrieve a private packet-based address of the particular subscriber on the basis of the particular public telephone number. An introductory message is provided to the caller and prompts the caller to leave a message. The ESP accesses the particular subscriber based on the particular subscriber private packet-based address to establish an audio connection via the communication medium. The subscriber is notified of the first call. If the subscriber answers the call, a communication path is provided between the caller and the subscriber via the communication medium so that the subscriber may hear the caller leave the message but the caller does not hear or know that the particular subscriber is listening. The ESP connects the caller and the subscriber for two-way communication upon the authorization of the subscriber. In another embodiment, both the caller and the subscriber use a packet-based network. The ESP may also record the caller's voice in response to the prompt, and play the recording to the subscriber if the subscriber answers the call.
The system disclosed in U.S. Pat. No. 6,353,660, incorporated herein by reference, operates via PSTN switches. Screening is done not by voice of source subscriber but rather by predetermined criteria such as source ID as accessed from a database that correlates a public (PSTN) telephone number with an IP address. As explained with reference to FIG. 7 of U.S. Pat. No. 6,353,660, the called party may have a designated voice mail system but this serves the sole purpose of recording a message from the calling party only in the event that the called party does not answer an incoming call or rejects it. Thus, the voice mail is provided only for redirecting calls without contacting the called party first (mainly according to the time of the call/business hours). Screening is not performed by the voice mail system but rather by the ESP, which vocalizes a message prompt that is routed to the source. But in order to prompt the target telephone, the ESP must also call the target telephone. Even if a special tone or ringing signal is used that identifies the new call as originating from the ESP, the target subscriber must still answer the call in order to hear the message recorded by the source subscriber. Thus, from the perspective of the called subscriber, until he or she answers the incoming call, there is no way of knowing the identity of the calling party. This means, that the called subscriber will be disturbed to the extent of answering the telephone merely in order to ascertain the identity of the calling party. This is inconvenient even in the event that it transpires that connection to the calling party is required; but if, in fact, no such connection is required the interruption is all the more undesirable.
U.S. Pat. No. 5,625,676 published Apr. 29, 1997 assigned to Active Voice Corporation and entitled “Method and apparatus for monitoring a caller's name while using a telephone” discloses a method and apparatus for an auto attendant system to allow a called party to monitor a screening name left by a caller while the called party is on the telephone with a third party. If the called party wishes, the system can place the third party on hold and connect the caller. Alternatively, the system can redirect the caller to another line or ask the caller to hold. The system is implemented with a second communication channel from the telephone switch system to the called party so that the called party can monitor the screening name left by a caller without first putting the third party on hold or disconnecting from the third party. The system can be configured to automatically monitor each screening name as it is left, without intervention by the called party.
The system disclosed in U.S. Pat. No. 5,625,676, incorporated herein by reference, uses a data network in addition to the regular PSTN and stores voice messages in a server connected to the data network. In one embodiment, all incoming calls are screened and an interactive voice response prompts the calling party to state his or her name. This analog voice information is routed via the regular telephone line to the server where it is converted to data and conveyed to a computer for display thereby. The computer is typically located alongside the called party's POTS telephone extension, so as to allow the called party to see the identity of the calling party and thus decide how to react.
This system also relates to communication initiated in a regular PSTN. The system fails to provide automatic voice screening in an IP LAN where both calling and called parties communicate using VoIP. Moreover, the server operates as a voice mail system and the system is not adapted to extend the utility of a conventional voice mail system for use with VoIP. Also, the called party requires a separate computer to monitor an incoming call and this renders such an approach expensive since each user requires a dedicated computer.
Our co-pending U.S. application Ser. No. 10/739,196 entitled “Method and apparatus for providing a Central Telephony Service for a Calling Party at the Called Party telephone” incorporated herein discloses an improved telephone handset that may be used in a voice mail system in order for the target telephone to achieve two media-related operations:                Bridging the voice stream between a calling party and the voice mail; and        Summation of both bridged streams into one stream which is sent to the target telephone's speaker.        
Such an approach is suitable for use with POTS or VoIP telephones or any combination thereof and obviates the need to modify the voice mail system, although it requires a modified telephone handset for use with such a system.
It would therefore be desirable to allow a voice mail system to operate in conjunction with any telephone network, including VoIP networks, so as to provide call screening and answering without the need for a modified telephone handset.